This invention relates to stringed instrument soundboards, to stringed instruments containing such soundboards, and to methods of making the soundboards.
It is desirable that a stringed instrument be as lightweight as possible, as an incremental increase in weight degrades the loudness and tonal quality of the instrument. Generally, it has been necessary to internally brace the soundboard (e.g., soundboard 14, FIGS. 1 and 1A) of the instrument, as wooden soundboards that are made thin enough to provide good sound are not sufficiently stiff to withstand string tension without buckling, distortion or even structural failure. Internal bracing adds weight and also adds complexity and cost to the manufacturing process.
When manufacturing a stringed instrument, the luthier (stringed instrument maker) strives to obtain the finest sound quality possible, while also producing an instrument having a fine surface finish and attractive appearance. These goals tend to be conflicting, as the surface coatings, e.g., varnishes and lacquers, that are applied to obtain an attractive, glossy surface generally detract from the sound quality of the instrument by adding weight and additionally producing tonal distortion.
Obtaining a fine surface finish also tends to be very labor-intensive. Traditionally, luthiers have repaired surface defects and porosity by manually filling defects and pores with a filling resin, e.g., by dipping a toothpick in the resin and daubing the toothpick on each defect, sanding the surface smooth, applying a varnish, and polishing the surface. Each of these steps may have to be repeated several times for each of hundreds of defects to obtain a high quality surface finish.
Other alternative methods of obtaining a smooth surface with non-wood materials, such as curing a composite material under autoclave conditions, or applying a gel coat to the mold, are generally expensive and/or result in unacceptable tonal quality.